Process of making storage-battery electrodes and filling mass therefor.



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WLLIAM' .RIDER-ISSN, 0F CHICAGO, ILILNIS.

specification of Letters Patent.

No. Drawing.

b all 14u/tom mag! concern Ele it lrnown that ljlliLLiAM Monnison, eCitizen of the United States, residing at Chicago, in the county of CookandState of Illinois, have invented certain new and useful Improvementsin llroeesses of Making Storage- Battery Electrodes and Filling MassTherefor, of which the following is a specification.v

This'invention relates to lead storage battery electrodes of thepasted-grid type, and comprises e novel process applicable for theproduction oi both nevative and positive plates. The invention eomprisesalso a novel filling-mess forsuch electrodes. ltis characteristic otstorage battery electrodes prepared as hereinafter described that theymay be subjected to one or several reversals iu the course of which theyare completely discharged and fully recharged with reversed polarity,and that this may be done not merely Without injury to the plate, butsuch reversals add materially to the capacity of the electrode. 1

The preparation ot the plate will now be described by reference to spreferred procedure, it being understood, however, that my invention isnot restricted to the particular proportions of materials or concentrations of acid set forth by Way of orfaniple: nor is my inventionlimited to the performance of all of the n'ianipuletions and steps whichconstitute my preferred procedure, which is as follows:

l' first prepare an acid reagent containingl sul-furie acid diluted withabout 10% or moreby volume oteommercial '(3%) hy drogen peroxidsolution, the proportion ot acid beingn such that the speciio ,gravityof the mixture is approximately 1325 (Wet-er 1000). To about 4.5gallons-et this acid l'iouid .contained in a stoneware or other suitablevessel, l. add with stirringl about 11S lbs. of a mixture which maycomprise aim proximately three parte oi li'tharge (Phil) and one part ofred leed (PbOq-)Q ln the course oit this operation, when properlyconducted, e stroman evolution of heet and a progressive thickening; otthe mixture are observedq .accompanied by bubbling of the 4inass andabondent evolution of gas (o:ry-

Avagen) and steam. ln e typical. operation t e 'temperature to or abovethe boiling Fatented Nov. it?,

Application filed. February 23, 1918. Sera1Ne.f18,73

point of yvater, the precise temperature reached being dependent among;-other iactors, upon the scale ol operations, :luid the rate of additionot the lead oxid.

As soon as the initial energetic reaction has subsided, the still moistmass or heavy paste ig; preferably packed into suitable oontainers andpermitted to cool slowly, say tor 24 hours, duringl which period the raction proceeds to completion. At the end Koit this. time the product isa rather friable, reddish-brown solid, which should be quite free troniuncombineol acid. rlfhis product is substantially stable, by which lfmean that it does not exhibit any substantial or material tendency tospontaneous setting or har- @lening when stored in bulk` unlesssubjected to sufficient pressure to initiate such setting, as describedbelow.

The function of the hydrogen peroxid, which as is known is capable whenin acid solution of acting as a reducing,- agent, is to effect thereduction to a lower oxid of lea-d ofthe peroxid component of the redlead, which latter may be regarded as a compound or miXture representedby the :formule QPbUPbOg. At the conclusion of lthis stage of theprocess the mass should preferably leave little or no residue of peroXidwhen treated 'with dilute nitric acid. The presence of anyconsiderable'residue of lead peroxid when so treatcdindicates aninsutlicieney of" hydrogen peronid in the acid mixture. I may use anoxid mixture containing either more or less red lead than specifiedabove, the proportion ot the reducino; agent, as hydrogen peroxid, beingpreferably appropriately altered. As above stated the properly preparedfilling-mass may be kept in bulk for long 1 eriods without becoming hardand unwor able.

The rather triable, acid-free filli ngrnass prepared as above is nowpreferably rubbed or Worked under the spatula or by any appropriatemechanism until it becomes plastiic and somewhat puttydilre inoonsistence. ln this state it is pasted and closelypaclred into thegrids, the precaution being taken to so completely fill the grids thatin the subsequent pressing step a suttleieut pressure will be exertedupon the lling.

The pasted-grids are subjected, preferably between absorbent pads, suchas blotting itil Milli Y ss i stated, the battery may paper, to a shortor even momentary. high ressure in a hydraulic or other press, apressurel approximating one ton or somewhat less per square inch ofsurface being satisfactory in practice. The pressed plates are thenpreferably closely packed in order that they may retain for a reasonableperiod their residual moisture and to prevent a too rapid and vhardsetting of the filling-mass, which should retain a definite althoughrelatively slight degree of plasticity or softness until it is submittedto the electrical forming process. As heretofore stated, the effect ofthe pressure to which the filling-mass is subjected is to initiate thesetting or hardening thereof.

The plates are now assembled into groups, alternately positively andnegatively connected, with suitable separators -or spacing devices', asfor-example ribbed and perforated hard rubber Isheets. The assembledplates are preferablv immersed in water for a few minutes, or until theinterstices or pores of the filling-mass are completely filled. The

plates are then formed by immersmg the group in an acid electrolyte, forexample, sulfuric acid of specific gravity 1025, and passing theAcurrent until the positive plates are fully oxidized and the negativeplates fully reduced. The plates are then preferably permitted todischarge to an extent at least equal to their rated capacity, before'removing them from the electrolyte. The preparation of the electrodesmay now be regarded as complete, although as above be completelydischarged and re-charged with reversed polarity. this reversal beingrepeated several times if desired andvresulting in a material increasein the capacity of the electrodes.

In-explanation of the purpose of saturating the plates with waterimmediately before the electrical 'forming process, it is pointed outthat the proportion of sulfuric ncid to the oxids of lead in theoriginal mix ture is insufficient to yield the white sulfate of leadunder the described operating conditions, although sufficient toprovide, in the filing-nnass. a materially larger proportion of thesulfate radical than could bev taken up by the active material in anysubsequent running down of the battery under conditions of use. Afurther treatment of the dry filling-mass with sulfuric acid would,however. tend to the formation of such white sulfate. the elimination ofwhich can only be accomplished by a relatively large expenditure ofcurrent during the operation of forming. The eect of the dipping orsaturating treatment is to fill the pores of the ,plates with water,which so far prevents access of the sulfuric acid electrolyte to theinterior of the plates that the formation of sulfate li's.

avoided and. the forming process is accomplished relatively quickly andwith comparatively small external electrolyte.

` ess, a satisfactory lbe avoided, and

' peroxid-free a be omitted without departing from expenditure ofcurrent. The introduction of sulfuric acid into the interior of theplate is further minimized by the use of relatively dilute acid (1025specific gravity) for the forming electrolyte, this electrolyte, ofcourse, increasing in gravity durin the forming process as the sulfuricaci radical is eliminated from the lactive material. In other words,during the forming process, the liquid within the active mass is ofmaterially lower concentration and therefore of lower electricalconductivity than the It results from this condition that the (oxidationor reduction) starts in the main at the external areas in contact'withthe grid, and extends progressively throughout the mass of activematerial. I have found that under these conditions the reduction may beaccomplished with much greater rapidity,I It will be .'understood,however, that plates prepared as hereindescribed may be electricallyformed directly in sulfuric acid withoigt previous-immersion in water,especially if the plates have not been permitted to dry out too far,although as above pointed out this requires a materially greaterexpenditure both of time and currentvwhenever the conditions are suchthat sulfating sets in.

My invention is not limited to the use of hydrogen peroxid as a reducingagent for the higher oxids of lead, inasmuch as other reducing agents,including oxalic acid,ffor maldehyde, metallic peroxids, etc., arecapable of producing somewhat similar results. I prefer, however, to usehydrogen peroxid for reduction purposes, inasmuch as it yields noreaction product of an objectionable or difficultly removable nature.

A principal object of using a certain proportion of red lead inconjuction with litharge is to improve the texture of the fillingmass.This is not necessary, however, in every case, inasmuch as there existcornmercial grades of litharge which are capable of yielding. under theconditions of my proccommercial plate. Commercial litharge oftencontains, however, considerable proportions of lead peroxid, thepresence of which in the filling-mass is to therefore even when the redlead is omitted I prefer to use sufficient peroxid of hydrogen toproduce a substantially filling-mass, as indicated above. 1n case alitharge substantially free from peroxid of lead and unmixed withred'lead were used, the reducing agent may, of course,

` my invention.

1. The hereindescribed process of preparing a storage battery electrode,comprisling sulfuric acid and lithar'ge ing comming Y under conditionsto initiate an energetic rerescues action and to produce a non-acid,stable lilling-niass; transferringF tne tlllinganass tc a grid orsupport and subitctina` it therein to Suicient pressure to initiate tbesetting or hardening" of the mass, and electrically forming the plate.

2. The hereindescribed process of prepar ing' a storage batteryelectrode, comprising connninglinn' sulfuric acid and litliarge underconditions to initiate an energetic reaction and to produce a non-acid,stable :lillingniass; transferring the lli119g-iiiass to a ,arid orsupport and subiectine it therein to sufficient pressure to initiate thesetting or hardening of the mass, and electrically forming the platebefore the filling-mass has attained. its maximum hardness or set.

The hereindescribed process of preparing a storage battery electrode,comprising comming'ling sulfuric acid and litliarge under conditions toinitiate an energetic reaction and to produce a. non-acid, stableillingmass; transferring the filling-mass to a grid or support andsubjectingr it therein to sufficient pressure 'to initiate the settingor hardening,Ir of tbe mass, saturating tlieplate With Water, andelectrically forming the plate in sulfuric acid solution.

4. The liereindescribed process of prepar- 111g' a storage batteryelectrode, comprising comminglinp; sulfuric acid and litharge underconditions to initiate an energetic reaction and to produce a non-acid,stable filling-mass; transferring the filling-mass to a grid or supportand subectinp; it therein -to sufficient pressure to initiate the seting or Vhardening' of the mass, saturating the plate with water beforethe filling-mass llas attained its maximum hardness or set, andelectrically foriningtlie plate in vsulfuric acid solution.'

The hereindescribcd process of preparing a storage battery electrode,comprising coinniine'ling sulfuric acid, lower and higher oxids oflead., and a substance capable of reducing said higher oxid, undercond1t1ons to initlatean energetic reation;

transferring' tlic resulting filling-mass to a grid or support andpressing?,` it therein, and electrically forming the. plate'.

6. The hereindescribed process of preparing a storage battery electrode,comprising conimingling sulfuric acid, lower and higher oxide of lead,and hydrogen peroxid, under conditions to initiate an energeticreaction; transferring tlie resulting filling-mass lto a 'grid orsupport and subjectingit therein to sufficient pressure tc initiate thesetting or 'hardening of the mass, and electrically forming' the platebefore the llingsnass has attained its maxin'ium hardness or set.

7. The hereindesfiribed process of preparing a storage batteryelectrode, comprising,- commingling sulfuric acid, a mixture of lthargeand red lead. and a substance caing a pable of reducing;r the pcrioXidcomponent of the red lead, under conditions to initiate an energeticreaction; transferrina` tlie result-- ing lillinganass to a grid orsupportand pressing it therein, and electrically fcrniiifg the plate. y

8. The liereindescribed process of preparstorage battery electrode,comprising comniingling sulfuric acid. a mir-turc of litliarge and redlead. and hydrogen peroxid, under conditions to initiate an encrgeticreaction, transferring tlie resulting filling-mass to a grid or supportand pressing it therein, and electrically forming the plate.

9. ln a process of preparing a storage bat` tery electrode, tlie step ofproducing a filling-mass which comprises commingling sul-4 furic acidand litliarge under conditions to initiate an energetic reaction, andcontinuing the reaction until a solid, somewhat friable, andsubstantially stable reaction product is formed.

l0. ln a process of preparing a storage battery electrode, the step ofproducing a fillingunass which comprises coinmingling sulfuric acid,lower and higher oxids of lead, and a substance capable of reducing;said higher oxid, under conditions to iniM tiate an energetic reaction,and continuing the reaction unt-il a solid, somewhat friable, andsubstantially stable reaction product formed.

ll. In a process of prei'iaring a storage' 13. As a new article ofmanufucture, the.

liereindescribed lilling-rnassfor lead storage batteries, said massresulting); from reaction of. sulfuric acid upon lower and higher oXidsof lead'in presence of a substance capable of reducing said higher oXid.characterized by its substantial stability or freedom from tendency tospontaneous setting or hardenm ing, but capable of hardening rapidlyafter subjection to suilicient pressure.

la. As a new article of manufacture, tbe liereindescribed lling-mass forlead ster age batteries, said mass resulting freni reaction of sulfuricacid upon lower and liigber oXids of lead in presence of hydrogen pernoxid, characterized by its substantial stabil ity or freedom rcnatrai.dence to spontane- ,battery electrode,

Vous setting or hardening, but capable of hardening rapidly aftersubjection to suiiicient pressure.

15. In a'process of preparing a storage the step of producing alling-mass which consists in commingling sulfuric acid and lithargeunder conditions to initiate an energetic reaction with strong evolutionof heat, and completing the reaction at a lower temperature, whereby asubstantially acid-free, stable filling-mass is produced.

16.` In a process of preparing a storage battery electrode, the step ofproducing a illing-mass which consists in commingling sulfuric acid,lower and higher oXids of lead, and a Substance capable of reducing saidhigher oXid, under conditions to initiate an energetic reaction withstrong evolution of heat, and completing the reaction at a lowertemperature, whereby a substantially acidfree, stable filling-mass isproduced.

17. The hereindescribed process of preparing a storage batteryelectrode, comprising commingling sulfuric acid, lower and higher oXidsof lead, and a substance capable of reducing said higher oXid,transferring the resulting filling-mass to a grid or plate and pressingit therein, saturating the plate with water, and electrically formingthe plate in a sulfuric acid solution.

18. In a process of preparing a storage battery electrode, the stepwhich Consists in saturating the iilling-mass with an aqueous liquid ofrelatively low electrical conductivity, and then forming the plate in auelectrolyte of higher conductivity.

19. In a process of preparing a storage battery electrode, the stepwhich consists in saturating the filling-mass with water -and thenforming the plate in a sulfuric acid electrolyte.

20. In a process of preparing a lead storage battery electrode of thepasted-grid type, the method of increasing the capacity of the platewhich consists in electrically Copias o! this patent may be obtained forforming the plate, completely discharging the same, and reforming withreversed polarity.

21. In a process of preparing a lead storage battery electrode of thepasted-grid type, the method of increasing the capacity of the platewhich consists in electrically 'forming the plate, completelydischarging the same and reforming with reversed polarity, and repeatingthe operation until the desired capacity is attained.

22. The hereindescribed process of preparing a storage battery electrodecomprising commingling sulfuric acid and oXid of lead, and continuingthe reaction until a solid, somewhat riable, and substantially stablereaction product is formed, the reacting materials being used in suchproportion that the reaction product contains a larger proportion of thesulfate radical than can be taken up by the active material in thedischarge of the battery.

23. There hereindescribed process of preparing a storage batteryelectrode comprising commingling suluric acid and lower and higher oxidsof lead and a substance capable of reducing said higher oXid, andcontinuing the reaction until a solid, somewhat friable, andsubstantially stable reaction product is formed, the reacting materialsbeing used in such proportion that the reaction product contains alarger proportion of the sulfate radical than can be taken upby theactive material in the discharge of the battery.

24. As a new article of manufacture, the

hereindescribed filling mass for lead storage batteries. said massresulting from the reaction of sulfuric acid upon cxid of lead, andcharacterized by containing a materially larger proportion of thesulfate radical than can be taken up by the active material in thedischarge of the battery.

In testimony whereof I affix my signature.

1WILLIAll/I MORRISON.

ve cents each, by addressing the Commissioner of Eatent'l,

Washington, D. C.

